9 - Emergency Department and Observation Unit Discharge Criteria

Editors: Peacock, W. Frank

Title: Short Stay Management of Heart Failure, 1st Edition

Copyright ©2006 Lippincott Williams & Wilkins

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Emergency Department and Observation Unit Discharge Criteria

Deborah B. Diercks

Heart failure (HF) causes substantial morbidity and mortality in the United States and is the most common principal discharge diagnosis in adults aged 65 years and older.1,2 and 3 Altogether, the costs for HF hospitalizations are approximately $14.7 billion per year.4 A substantial number of these patients present to the emergency department for the initial treatment of their acute decompensation. It has been suggested that 80% of all patients who present with acute decompensated heart failure (ADHF) are admitted to the hospital.5 Identifying patients who are suitable for discharge home or for admission to an observation unit (OU) may substantially reduce overall hospital costs. However, for emergency physicians, accurate disposition is a challenge and perhaps more daunting than the management of these patients.

Disposition decisions are often time-dependent and lack adequate time to assess response to treatment. This may result in inappropriate admissions and premature emergency department (ED) discharges, with resultant increased cost and morbidity, respectively.6,7 Although the American College of Cardiology (ACC)/American Heart Association (AHA) guidelines on the management of HF suggest that patients with mild to moderate symptoms generally do not require admission, risk assessment based on symptoms is often difficult.5 To increase the number of patients discharged to home, effective treatment must be initiated in the ED as part of their ED management or an OU protocol. This early intervention and avoidance of hospital admission can result in significant cost savings, because 75% of costs arising from hospitalization for HF are incurred within the first 48 hours.4

Success of any protocol is dependent on accurate identification of patients suitable for an early discharge plan. Patients with a high probability of adverse outcome, such as those with evidence of acute cardiac ischemia, should be admitted to the hospital as in-patients. Blood pressure and heart rate are two of the most significant independent predictors of acute


mortality in patients with ADHF;8 thus, patients with unstable vital signs, including a heart rate greater than 130 beats per minute, systolic blood pressure (SBP) less than 85 mm Hg or greater than 175 mm Hg after initial ED treatment, and O2 saturation less than 90%, are inappropriate for an early discharge strategy.9 In addition, patients with airway instability, inadequate systemic perfusion, or cardiac arrhythmias requiring continuous intravenous (IV) intervention, as well as those requiring invasive hemodynamic monitoring or receiving medications that require frequent uptitration, such as nitroglycerin, are also not suitable for an HF OU admission.9

As essential as the identification of appropriate patients for this rapid treatment protocol is, use of discharge criteria to result in a low rate of subsequent hospital readmission soon after discharge is also important. Unfortunately, there is a paucity of data addressing this issue in the ED, in-patient, and OU settings. Current methods of risk stratification have focused on identifying patients at risk for short- and long-term adverse events. Risk stratification is an ongoing process. It is dependent on clinical appearance, laboratory parameters, and response to acute therapies. Discharge to home should be considered from the perspective of an estimate of the acuity of the initial presentation of the patient, improvement in response to treatment, and risk of recidivism after discharge. It is suggested that certain clinical features should then alter the physician's initial acuity estimate and improvement in these parameters can identify patients suitable for discharge to home.

Consensus guidelines for discharge from the ED and OU have been developed.10 These guidelines are based on the presence of factors associated with increased risk for adverse events. Although the absence of these parameters does not ensure that a patient is ready for discharge, they are useful in identifying patients with persistent decompensated HF who would benefit from additional treatment. These discharge criteria can be divided into three categories: patient-centered measures, hemodynamic and clinical parameters, and laboratory results (Table 9-1).

It has been well established that patient-centered outcome measures, such as a change in dyspnea, can be used to assess therapeutic success and improvement in symptoms. Although subjective, the measurement of dyspnea on a seven-point or three-point scale is a validated outcome measure.11 In addition, the assessment of dyspnea has been shown to correlate with hemodynamic status in clinical trials. However, no study has evaluated this as an endpoint in an ED or OU, although it continues to be assessed in informal manners.11 Another patient-centered measure that should be present at the time of discharge is the lack of ongoing chest pain. It has been reported that acute coronary syndrome (ACS) is a trigger for up to 25% of HF decompensation. Therefore, patients should be pain free or have undergone an evaluation for ACS prior to discharge.12 Finally, the patient should be able to ambulate without an increase in dyspnea from baseline. Although no trial has assessed this measure in an OU setting, it effectively is an inexpensive 6-minute exercise test. The distance that


a patient can ambulate in a 6-minute period without excessive dyspnea and fatigue has been shown to correlate with long-term mortality. Unfortunately, many comorbid illnesses, such as obesity and lung disease, affect this outcome measure; hence, it is important to assess a change from baseline.13 In addition, freedom from symptoms of congestion such as orthopnea has also been associated with improved long-term outcomes.14

TABLE 9-1 Discharge Criteria

Patient Measures
No chest pain that would raise concern for acute coronary syndrome (ACS)12
Improvement in dyspnea11
Ability to ambulate without dyspnea above baseline13
Free of symptoms of congestion14
Hemodynamic/Clinical Parameters
SBP <160 mm Hg, >90 mm Hg15
No S3 on auscultation16
Improvement in thoracic electrical bioimpedance measurements19
Oxygen saturation >90%10
Urine output >1 L10
Decrease in weight/return to dry weight
Laboratory Results
BNP levels17,18 and 19
Stable creatinine17
Stable or declining troponin level20
Return to normal or baseline of electrolytes and blood urea nitrogen (BUN)22
BNP, B-type natriuretic peptide; SBP, systolic blood pressure.

Hemodynamic and clinical parameters can also be used as part of the data to assess suitability for discharge. These comprise measures of perfusion, volume status, and oxygenation based physical examination findings and automated measures. SBP is a useful predictor of adverse events at the time of presentation and discharge.15 In the initial presentation of patients with decompensated HF, a hypertensive response is adaptive; however, persistent elevation of SBP can correlate with increased risk of worsening renal function. This deterioration of renal function clearly correlates with morbidity and mortality; therefore, adjustment of medications to prevent hypertension is essential prior to discharge. Although the ideal blood pressure at the time of hospital discharge is not clearly elucidated, patients should at least have an SBP less than 160 mm Hg.15 In addition, as medications are titrated patients must be able to ambulate without symptoms of dizziness; therefore, patients should have an SBP greater than 90 mm Hg.10


Clinical findings can also be used to assess adequacy of acute interventions. These include a combination of changes in physical examination findings and easily obtained values, such as pulse oximetry, weight, and urine output. Of all the clinical examination findings, the presence of an S3 is most suggestive of acute decompensation.16 Serial examinations that can document the resolution of an S3 can be used as a discharge criteria.16 This physical examination finding, like an improvement in jugular venous distention, is dependent on physical attributes of the patient and careful physical examination assessment by the physician. Another criterion noted as part of the evaluation is oxygen saturation. Patients should have an oxygen saturation greater than 90%.10 No data exist to support this value; however, it is reasonable to discharge only patients who are able to maintain their oxygen saturation. Transient nighttime drops in oxygen saturation are common because HF is associated with an increased prevalence of obstructive sleep apnea. Therefore, pulse oximetry as a discharge criterion should be assessed when the patient is awake.

Urine output assessment is another parameter that can be used as a surrogate to assess treatment efficacy. Although there are no studies that compare the amount of urine output with outcomes, intuitively this makes sense. Clinically, 1 liter (L) appears to be a significant amount. Closely linked to urine output is a decline in patient weight.10 Dry weight is often one of the only baseline parameters that we know in the ED. Theoretically, a decline in the patient's weight can represent a resolution of the acute progression of the disease process; however, overshooting this parameter can lead to hypotension, hypoperfusion, and worsening renal function. Although not supported by clinical trials, it is reasonable to suggest that a patient's weight should be declining at the time of discharge; however, additional assessment may be warranted in patients who are below their dry weight at the time of discharge.

Improvement in laboratory results may be used to assess patients at the time of discharge. Studies have shown that a decline in B-type natriuretic peptide (BNP) levels is associated with improved morbidity and decreased hospital readmission rate.17,18 and 19 However, no study has looked at the change in BNP levels in the less than 23-hour timeframe. It makes intuitive sense that a patient's BNP should be declining at the time of discharge assessment, although the exact amount of decline is unknown. Elevated troponin levels have been shown to be predictive of long-term prognosis in HF patients.20 Patients with severe HF may have chronically elevated levels. However, a rise in troponin levels during an OU stay should provoke concern and may reflect inadequacy of treatment or the presence of ACS. In addition, patients with an elevated initial troponin level have been shown to be more likely to stay in the hospital greater than 24 hours and have a high rate of 30-day hospital readmission.21 Therefore, patients with an elevated initial troponin level are probably not suitable for an early discharge strategy.


Traditional chemistry laboratory tests that are routinely assessed daily in patients with decompensated HF can also be used in the assessment of a patient at the time of discharge. A sodium level of less than 136 mEq/L and a serum blood urea nitrogen (BUN) greater than 43 mg/dL have been shown to correlate with 1-year and acute mortality, respectively.8,22 Therefore, improvement in the BUN and serum creatinine in patients with abnormal values is a potential marker of treatment success and may be useful in determining disposition.23 At this point, there are no trials that have used these values in this capacity. Recently, a significant amount of attention has been placed on the significance of worsening serum creatinine in the setting of treatment for decompensated HF. A recent study has shown that an increase in creatinine level of greater than 0.3 mg/dL from hospital admission correlates with greater rates of in-hospital death, increased complications, and longer length of stay. The presence of worsening renal insufficiency as defined by a creatinine change greater than 0.3 mg/dL from prior values is concerning, and therefore patients warrant further treatment until the creatinine improves or stabilizes.24

Independent of the clinical presentation, the success of early discharge is dependent on adequate outpatient follow-up and appropriate medication adjustment at the time of discharge. The initial improvements gained in the ED or OU can be quickly negated if the patient is discharged without a suitable outpatient management plan. Key components include close follow-up to ensure adequate medication adjustment, dietary education, and a management plan (Table 9-2). An important component of outpatient HF disease management includes25,26 a cohesive management plan, which has been shown to result in a 25% to 75% reduction in hospitalization.27,28

TABLE 9-2 Outpatient Key Components

Nursing case management
Physician follow-up (primary care coordinated with cardiology)
Optimization of medication regimen
Patient education
Social support (home health assessment)

Optimizing the medical regimen is another complex portion of the disposition process, because it requires coordination among many providers, including the treating ED physician, OU treating physician, consultants, and the outpatient provider. Although beyond the scope of this chapter, medication considerations should include the titration of loop diuretic, spironolactone, angiotensin-converting enzyme inhibitor, beta-blockers, and possibly nitrates.25,26

It should also be noted that every patient will not fit every criterion and that every recommendation must be interpreted with the patient's


baseline status as well as their follow-up care in mind. The best recommendations contain a combination of these mentioned parameters adjusted for the individual patient. Using a combination of patient-centered outcomes and more objective measures provides ample evidence that can help drive the disposition decision. Appropriate discharge from the emergency room or OU must be accompanied with adequate follow-up. Also extremely important is patient education on dietary recommendations, medication schedules, and tracking body weight to help prevent the need for further emergency room visits or hospital admissions.


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